For years, we've used the formula "220 -C age" to calculate MHR, then multiplied the MHR by certain percentages to determine the right heart rate "zones" to exercise in: 50 to
70 percent (MHR x .5 to .7) for an easy workout. 70 to
85 percent (MHR x .7 to .85) for a moderate workout.
read more >>